Adhesive tapes are typically comprised of a flexible substrate, such as paper, plastic, or cloth that has a layer of adhesive material applied to at least one side of the substrate. The adhesive layer commonly covers the entire surface of one side of the substrate or can be disposed along only one longitudinal edge thereof. Such devices are commonly referred to as masking tapes suitable for protecting or masking respective portions of a surface to which liquids, such as paint, is applied wherein it is desired to generate a clean or crisp edge between the portions associated with the masking material.
Such masking tapes commonly include an adhesive that is applied as a generally very thin uniform layer across one or both of the faces of the substrate. Some manufacturers also provide masking materials wherein a respective edge of the masking material includes an adhesive that is applied to one side of the substrate and a liquid resistant material or plastic strip that is applied to the other side of the substrate to prevent contact of the liquid with the adhesive supporting substrate in an effort to improve degradation resistance of the substrate material when subjected to wet liquids. U.S. Pat. Nos. 1,726,744; 1,779,588; 2,171,544; 2,510,120 each suggest masking materials wherein relatively thin layers of adhesive are disposed along at least an edge portion of a strip of flexible substrate. U.S. Pat. No. 3,032,181 suggests a narrow band of adhesive on one or more edges of the tape and a corresponding coating on the back side of the tape to prevent adhesion and facilitate release of the adhesive from adjacent layers of the substrate when the masking material is provided as a roll.
U.S. Pat. No. 6,828,008 suggests placement of an absorbent layer on an edge of the substrate to at least substantially prevent liquids from being absorbed into the substrate and to retard the curing of liquids that may be applied to masking material. U.S. Patent Application Publication No. 2008/0318038 A1 teaches a masking material having a strip of liquid repellant material on a side of the substrate opposite the adhesive intended to prevent liquid material from adhering to the masking material.
Many of the aforementioned patents have been promoted in the marketplace as having edge sealing ability or edge blocking technology intended to prevent seepage of the liquid materials to that portion of the application surface that underlies the masking material and to maintain the integrity of the masking material to facilitate efficient removal of the same after the respective application process. Each of the disclosures referenced above attempt to resolve the long existing problem of providing a masking material that can withstand the application of liquid materials to the edge of the masking material and to do so in a manner that attempts to prevent seepage of the liquid materials to the portion of the application surface disposed generally behind the masking material. Those familiar with such products, and applicants testing associated with the present invention, clearly demonstrate that the currently available masking products perform in a manner that results in a less than desirable finished product.
The effectiveness of such masking products to prevent seepage is largely dependent on the roughness of the surface intended to be masked and when the surface is not smooth to even a small extent, seepage occurs and a clean sharp edge is not obtained. The root cause of such seepage is capillary action, or capillarity, which is the ability of a liquid to flow into very narrow spaces without the assistance of, and in opposition to external forces like gravity. The effect can best be seen in the drawing up of liquids between the hairs of a paint-brush, in a thin tube such as those used for biological or chemical testing, in porous materials such as paper, in some non-porous materials such as liquefied carbon fiber, or in a cell. Such capillary action occurs because of inter-molecular attractive forces between the liquid and solid surrounding surfaces. If a leakage path is sufficiently small, then the combination of surface tension, which is caused by cohesion within the liquid, and adhesive forces between the liquid and container act to force the liquid into the crevice or gap. Such capillary action is inadequately considered in many masking materials where small voids can be formed between the masking material and the treatment surface.
Although many of the masking materials referenced above can exhibit suitable seepage results when applied on truly planar surfaces, many if not all surfaces associated with painting activities are rarely truly planar. Particularly, the proliferation of textured wall and ceiling surfaces has proven such masking materials to have only very limited ability to adequately mask the respective portions of surfaces or adjacent surfaces for painting applications. The shortcomings of such products to adequately mask somewhat rough surfaces, such as sand textured, knock-down, orange peel, stucco or other cosmetic surface treatments is readily apparent to most users who have attempted to generate a line of demarcation between alternate liquid materials or colors applied to such surfaces.
While many of the companies that produce masking materials constructed in accordance with the patents cited herein advertise that their technology prevents paint from seeping under the edge of the tape, such assertions have shown only very limited authenticity with respect to surfaces that are not clean and very smooth, such as those encountered in most structures where the wall surfaces are “sand” or “textured” to some or even any extent. As demonstrated below with respect to the description provided with respect to FIG. 7, such assertions are frequently unsuited to replication to real life applications.
Therefore, there is a need for a masking material that can withstand the rigors of being subjected to liquid materials, can be removed from an underlying treatment surface without degradation or separation of the respective portions of the masking material, and can tolerate deformation of the masking material to match the contour of the underlying treatment surface to reduce or eliminate seepage behind the masking material while facilitating efficient removal of the masking material.